Until now, there have been various pigment inks proposed for use in inkjet recording, including a color pigment ink used in an ink set according to the present invention. The color pigment ink is disclosed in PTL 1, which concerns a prior application of the present applicant (such as a color pigment ink disclosed in Example 1 of the PLT 1).
According to these inventions of the prior application, image density, ejection stability, storage stability, and the like, can be improved for an inkjet recording process in which a black pigment ink and a color pigment ink are used separately. However, a problem of color-spreading may not be allowed for and solved for the inventions of the prior application in which the black pigment ink and the color pigment ink are ejected simultaneously.